Relay unit and electrical junction box

ABSTRACT

A relay unit and an electrical junction box are disclosed as including a plurality of relays ( 2 A˜ 2 D) and a power supply bus bar ( 3 ) for supplying electric power to the plurality of relays ( 2 A˜ 2 D) which are contained in an electrical junction box, wherein electric power is supplied to the respective relays ( 2 A˜ 2 D) from the power supply bus bar ( 3 ) via relevant fuses ( 16   a   ˜16   d ).

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a relay unit having a pluralityof relays, and a relay to be applied to such a relay unit, and anelectrical junction box in which such a relay unit is mounted.

[0002] A relay box, which serves as an electrical junction box which anattempt has heretofore been made to be improved, is disclosed in FIG. 1.

[0003] In FIG. 1, the relay box 120 is comprised of a relay cavity 121,a fuse cavity 122, a FL cavity 123 and a bus bar 124, with respectivecavities 121, 122, 123 receiving electronic component parts such as arelay, a fuse and a FL. The bus bar 124 provides an electricalconnection for the respective cavities 121, 122, 123. Further, therespective cavities 121, 122, 123 are inserted with pressure connectionterminals, each coupled to an electric wiring through a pressureconnection, through which desired electric signals are inputted oroutputted. With such a structure, the relay box 120 is formed with adesired relay circuit.

[0004] However, in the relay box 120, since the relays and the fuses arepositioned at separate locations, respectively, the relay box 120 hasbeen inevitably increased in size.

SUMMARY OF THE INVENTION

[0005] The present invention has been made with a view to addressing theabove issues and has an object to provide a relay unit and an electricaljunction box which has a fuse and which is compact in structure.

[0006] According to a first aspect of the present invention, there isprovided a relay unit comprising: a plurality of relays; and a powersupply bus bar supplying power supply current to said plurality ofrelays; wherein said power supply bus bar allows power supply current tobe supplied to said plurality of relays via respective fuses.

[0007] With such a structure, it is possible to provide the relay unitin which the plurality of fuses are contained in close proximity to theplurality of relays. Further, since electric power current is applied tothe respective fuses by means of the power supply bus bar, there is noneed for discrete electrical wirings for electrical connection, with aresultant improved workability in assembly of the relay unit.

[0008] According to a second aspect of the present invention, there isprovided an electrical junction box comprising: a plurality of relays;and a power supply bus bar supplying power supply current to saidplurality of relays; wherein said power supply bus bar allows powersupply current to be supplied to said plurality of relays via respectivefuses.

[0009] With such a structure, since the plurality of relays and thepower supply bus bar are contained together within the electricaljunction box to allow power supply current to pass through therespective fuses to the plurality of relays, the electrical junction boxis formed in a compact and simple structure while an assemblingworkability is highly improved.

[0010] Other aspect and advantages of the invention will become moreapparent from the following description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a plan view of a relay box which an attempt has beenmade to be improved by inventors of the present patent application;

[0012]FIG. 2 is a structural view illustrating basic bus bar circuitcomponents and a power supply bus bar component of a relay unit of afirst preferred embodiment according to the present invention wherein;

[0013]FIG. 3 is a circuit diagram of the relay unit shown in FIG. 1under a condition prior to trimming operation of trimmer joint portionsintervened between the basic bus bar circuit components;

[0014]FIG. 4 is a view illustrating circuit diagrams of objectcircuitries Nos. 1 to 4 which are formed by trimming the trimmer jointportions of the basic bus bar circuit components and associated bus bartrimming and conducting patterns;

[0015]FIG. 5 is a view illustrating circuit diagrams of objectcircuitries Nos. 5 and 6 which are formed by trimming the trimmer jointportions of the basic bus bar circuit components and associated bus bartrimming and conducting patterns;

[0016]FIG. 6 is a view illustrating circuit diagrams of objectcircuitries Nos. 7 and 8 which are formed by trimming the trimmer jointportions of the basic bus bar circuit components and associated bus bartrimming and conducting patterns;

[0017]FIG. 7 is a view illustrating a circuit diagram of an objectcircuitry No. 9 which is formed by trimming the trimmer joint portionsof the basic bus bar circuit components and associated bus bar trimmingand conducting patterns;

[0018]FIG. 8 is a circuit diagram illustrating a detailed example of apractical mounting circuit forming the relay unit of the first preferredembodiment according to the present invention;

[0019]FIG. 9 is a structural view illustrating trimmed conditions andassociated circuit patterns which form the practical mounting circuit ofthe relay unit of the first preferred embodiment according to thepresent invention;

[0020]FIG. 10 is a cross sectional view (which involves a front view ofa relay according to the present invention) of an electrical junctionbox of a second preferred embodiment according to the present invention;

[0021]FIG. 11 is a plan view of the electrical junction box shown inFIG. 10;

[0022]FIG. 12 is an enlarged view illustrating connector portionsbetween the relays and the relevant fuses shown in FIG. 10; and

[0023]FIG. 13 is a cross sectional view of an electrical junction box ofa third preferred embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] To describe the present invention more in detail, a relay unit ofa first preferred embodiment of the present invention will be explainedbelow with reference to FIGS. 2 to 9, wherein FIG. 2 is a structuralview illustrating a basic bus bar circuit body 4 and a power supply busbar 3 which form a relay unit 1 of the first preferred embodiment, FIG.3 is a circuit diagram of the relay unit 1 with a plurality ofelectrically conductive trimmer joint portions 9 a to 9 j, formed in thebasic bus bar circuit body 4, shown in a state prior to trimmingoperation.

[0025] As shown in FIGS. 2 and 3, the relay unit 1 is comprised of foursets of laterally arrayed relays 2A to 2D which is located in a unitcase (not shown) in close proximity relationship to one another in thesame horizontal plane, and the power supply bus bar 3 located in an areaadjacent to the laterally arrayed relays 2A to 2D. The four sets ofrelays 2A to 2D include four relay switch element elements SW (see FIG.3), relay coil elements L (see FIG. 3) associated with respective relayswitches SW, and the basic bus bar circuit body 4.

[0026] The basic bus bar circuit body 4 is composed of laterally spaced,switch connector bus bars 5 a to 5 d and laterally spaced, switchconnector bus bars 6 a to 6 d placed in close proximity to the switchconnector bus bars 5 a to 5 d, respectively, to be correlated therewithfor forming respective pairs of switch connector circuit components eachfor the relay switch element SW, and laterally spaced, coil connectorbus bars 7 a to 7 d and laterally spaced, coil connector bus bars 8 a to8 d placed in close proximity to the switch connector bus bars 7 a to 7d, respectively, to be correlated therewith for forming respective pairsof coil connector circuit components each for the coil element L, withfour pairs of switch connector circuit components being located inparallel to one another which the four pairs of coil connector circuitcomponents are enclosed in the associated switch connector circuitcomponents. The basic bus bar circuit body 4 is further composed of theelectrically conductive trimmer joint portions 9 a to 9 j which areintegrally and preliminarily formed at suitable positions between therespective switch connector bus bars 5 a to 5 d, and 6 a to 6 d and therespective coil connector bus bars 7 a to 7 d and 8 a to 8 d. Thus, thebasic bus bar circuit body 4 is made of an electrically conductivematerial formed with a bus bar forming die of a single piece, with eachof the respective joint portions 9 a to 9 j being formed in a narrowwidth to provide an ease of cutting operation to thereby provide atrimming function.

[0027] In particular, the joint portions 9 a to 9 j are intervenedbetween one of the switch connector bus bars 5 a to 5 d and the otherone of the coil connector bus bars 7 a to 7 d within the same one of therelays 2A to 2D and intervened between each of the switch connector busbar pairs 5 a to 5 d and 6 a to 6 d and the other one of the switchconnector bus bars 5 a to 5 d. Suitably cutting a suitable part of theplurality of electrically conductive trimmer joint portions 9 a to 9 jallows a variety of selected relay circuit patterns to be readily formedas will be described below in detail. In FIG. 3, to provide aclarification, the basic bus bar circuit body 4 is formed with the jointportions, bearing the same reference numerals as those used in FIG. 2,which can be cut out for the trimming function by the cutting step.

[0028] The switch connector bus bars 5 a to 5 d, of one part of therelays 2A to 2D, have upper ends integrally formed with downstream fusejoint portions 11 a to 11 d, respectively, to be connected withrespective fuses, and lower ends integrally formed with connector jointrelay terminals 12 a, 12 e, 12 i and 12 m, respectively, to be connectedwith respective connectors. The downstream fuse joint portions 11 a to11 d protrude in respective fuse mounting areas (not shown) of the unitcase (not shown), and the relay terminals 12 a, 12 e, 12 i and 12 mprotrude into respective connector hood areas (not shown) of the unitcase (not shown). That is, the downstream fuse joint portions 11 a to 11d and the relay terminals 12 a, 12 e, 12 i and 12 m protrude indirections opposed to one another.

[0029] The switch connector bus bars 6 a to 6 d and both the coilconnector bus bars 7 a to 7 d and 8 a of the other part of the relays 2Ato 2D, have lower ends integrally formed with connector joint relayterminals 112 b to 12 d, 12 f to 12 h, 12 j to 12 l and 12 n to 12 p,respectively, to be connected with relevant connectors. The respectiverelay terminals 12 b to 12 d, 12 f to 12 h, 12 j to 12 l and 12 n to 12p protrude into the respective connector hood areas (not shown) of theunit case (not shown) in the same manner as the switch connector busbars 12 a, 12 e, 12 j ad 12 m of the aforementioned one part of therelays. That is, all the relay terminals 12 a to 12 p are formed inparallel to one another in the lower connector hood area (not shown) inwhich the relevant connectors are mounted to provide electricalconnections between the relay terminals and outside associated componentparts.

[0030] The power supply bus bar 3 is constructed of a laterallyextending main bar 3 a in the close proximity to upper distal edges ofdownstream fuse joint portions 11 a to 11 d of the relays 2A to 2D, fourupstream fuse joint portions 13 a to 13 d which project upward from themain bar 3 a, and a power supply terminal 14 bent downward from a leftdistal end of the main bar 3 a. The main bar 3 a is located on an innersurface in the unit case (not shown), with the four upstream fuse jointportions 13 a to 13 d being located in four fuse mounting areas (notshown) in the unit case (not shown), respectively. The four upstreamfuse joint portions 13 a to 13 d are aligned on respective positionsopposed to the downstream fuse joint portions 11 a to 11 d,respectively, with the upstream fuse joint portions 13 a to 13 d and thedownstream fuse joint portions 11 a to 11 d forming the sum of four setsof fuse joint section pairs 15 a to 15 d. In addition, the respectiveupstream fuse joint portions 13 a to 13 d and the respective downstreamfuse joint portions 11 a to 11 d are formed with cutout portions whichextend from respective upper edges in a downward direction. Insertingfuses 16 a to 16 d into the respective cutout portions of the fuse jointsection pairs 15 a to 15 d allows them to be fixedly mounted therein.

[0031] The power supply terminal 14 is formed such that it protrudesinto a power supply hood area (not shown) of the unit case (not shown)and is electrically connected to an associated external component partvia a connector (not shown) mounted in a connector hood area (notshown). Thus, the relay unit 1 has the structure to allow electric powerto be supplied from the power supply bus 3 to the four relays 2A to 2Dvia the respective fuses 16 a to 16 d.

[0032] Now, a detailed description will be given to show how an objectcircuitry is constructed by suitably cutting or trimming suitable partsof the plurality of trimmer joint portions 9 a to 9 j. FIG. 4 is a viewillustrating a circuit diagram for object circuitries No. 1 to No. 4 andassociated bus bar trimming and conducting patterns formed in the basicbus bar circuit body 4. FIG. 5 a view illustrating a circuit diagram forobject circuitries No. 5 and No. 6 and associated bus bar trimming andconducting patterns formed in the basic bus bar circuit body 4. FIG. 6is a view illustrating a circuit diagram for object circuitries No. 7and No. 8 and associated bus bar trimming and conducting patterns formedin the basic bus bar circuit body 4. FIG. 7 a view illustrating acircuit diagram for an object circuitry No. 9 and an associated bus bartrimming and conducting pattern formed in the basic bus bar circuit body4. In FIGS. 4 to 7, trimmer areas of the trimmer joint potions 9 a to 9j to be cut out are shown with black areas and non-trimmer areas of thetrimmer joint portions 9 a to 9 j are indicated with hatched areas.

[0033] The object circuitry No. 1 is a through-circuit which iselectrically conductive at all times to pass electric power currentthrough the fuse 16 a. For example, when using the relay 2A, electricpower is supplied from the power supply bus bar 3 and is outputted fromthe relay terminal 12 a. In this case, a desired object circuitry isformed by cutting out (trimming) all the trimmer joint portions 9 a to 9c related with the relay 2A.

[0034] The object circuitry No. 2 is a relay circuit wherein powersupply current is not supplied through the fuse 16 a and which is turnedon or turned off in response to a high or low level of a control signal(not shown). For example, when using the relay 2A, electric power issupplied from the relay terminal 12 a, and a pair of the relay terminals12 b, 12 c serve as a control terminal to output electric power from therelay terminal 12 d. In this case, also, a desired object circuitry isformed by cutting out (trimming) all the trimmer joint portions 9 a to 9c related with the relay 2A.

[0035] The object circuitry No. 3 is a relay circuit wherein powersupply current is supplied through the fuse 16 a and which is turned onor turned off in response to the high or low level of the control signal(not shown). For example, when using the relay 2A, electric power issupplied from the power supply bus bar 3, and a pair of the relayterminals 12 b, 12 c serve as the control terminals, respectively, tooutput electric power from the relay terminal 12 d. In this case, also,a desired object circuitry is formed by cutting out (trimming) all thetrimmer joint portions 9 a to 9 c related with the relay 2A.

[0036] The object circuitry No. 4 is a relay circuit wherein powersupply current is supplied through the fuse 16 a to the two relayterminals 12 c, 12 d which are electrically conductive at all times. Forexample, when using the relay 2A, electric power is supplied from thepower supply bus bar 3, allowing power supply current to be outputtedthrough the pair of the relay terminals 12 c, 12 d. In this case, also,a desired object circuitry is formed by cutting out (trimming) thetrimmer joint portions 9 b, 9 c without cutting out the trimmer jointportion 9 a among the trimmer joint portions 9 a to 9 c related with therelay 2A.

[0037] The object circuitry No. 5 is a power supply circuit whereinpower supply current is supplied through the fuse 16 a to the four relayterminals 12 c, 12 d, 12 g, 12 h which are rendered electricallyconductive at all times. For example, when using the relays 2A, 2B,electric power is supplied from the power supply bus bar 3 and isoutputted through the four relay terminals 12 c, 12 d, 12 g, 12 h. Inthis case, a desired object circuitry is formed by cutting out(trimming) the trimmer joint portions 9 c, 9 e, 9 f without cutting outthe remaining trimmer joint portions 9 a, 9 b, 9 d among the trimmerjoint portions 9 a to 9 f related with the relays 2A, 2B.

[0038] The object circuitry No. 6 is a relay circuit wherein powersupply current is supplied through the fuse 16 a and is branched intothe two relays 2A, 2B through which branched electric current flows aresupplied in response to the high and low level of the respective controlsignals to be applied to the relays 2A, 2B. For example, when using therelays 2A, 2B, electric power is supplied from the power supply bus bar3, allowing power supply current to be outputted through the relayterminals 12 d, 12 h with the actions of the respective controlterminals formed with the two pairs of the relay terminals 12 b, 12 c,12 f, 12 g. In this case, a desired object circuitry is formed bycutting out (trimming) the trimmer joint portions 9 a, 9 c to 9 fwithout cutting out the trimmer joint portion 9 b among the trimmerjoint portions 9 a to 9 f related with the relays 2A, 2B.

[0039] The object circuitry No. 7 is a relay circuit wherein powersupply current is supplied through the fuse 16 a and is branched intothe two branched power supply current flows which are controlled inresponse to the high and low level of a single control signal. Forexample, when using the relay 2A, electric power is supplied from thepower supply bus bar 3, and the pair of the relay terminals 12 b, 12 cserve as the control terminals, respectively, to output electric powerfrom the relay terminals 12 a, 12 d. In this case, a desired objectcircuitry is formed by cutting out (trimming) all the trimmer jointportions 9 a to 9 c related with the relay 2A.

[0040] The object circuitry No. 8 is a relay circuit wherein powersupply current is branched through the fuse 16 c into three branchedcurrent flows which are controlled in response to the high and low levelof the single control signal. For example, when using the relays 2C, 2D,electric power is supplied from the power supply bus bar 3, allowingpower supply current to be outputted through the three relay terminals12 l, 12 o, 12 p with the actions of the respective control terminalsformed with the pair of the relay terminals 12 j, 12 k. In this case, adesired object circuitry is formed by cutting out (trimming) the trimmerjoint portions 9 e to 9 g without cutting out the trimmer joint portions9 i, 9 j among the trimmer joint portions 9 e to 9 j related with therelays 2C, 2D.

[0041] The object circuitry No. 9 is a relay circuit wherein powersupply current is not supplied through the fuses 16 a to 16 d and thetwo relay terminals 12 c, 12 d are electrically conductive at all times.For example, when using the relay 2A, electric power is supplied fromthe relay terminal 12 a, allowing power supply current to be outputtedthrough the pair of the relay terminals 12 c, 12 d. In this case, adesired object circuitry is formed by cutting out (trimming) the trimmerjoint portions 9 b, 9 c without cutting out the trimmer joint portion 9a among the trimmer joint portions 9 a to 9 c related with the relay 2A.

[0042] It will now be appreciated from the foregoing description that adesired mounting circuit can be formed in an arbitrary combination ofeither one of or more than two object circuitries discussed above. Adetailed example of a practical mounting circuit will be described belowin conjunction with FIGS. 8 and 9, with FIG. 8 showing a circuit diagramwhile FIG. 9 showing a particular basic bus bar circuit body 4 formed ina particularly trimmed condition in a desired conductive pattern to formthe practical mounting circuit.

[0043] As viewed in FIG. 8, the mounting circuit is composed of theobject circuitries Nos. 3, 2 and 8, which are employed in a combinedstate. In the object circuitry No. 3, the relay 2A is employed under acondition where the three trimmer joint portions 9 a, 9 b, 9 c are cutout. Then, electric power is supplied from the power supply bus bar 3via the fuse 16 a, with the pair of the relay terminals 12 b, 12 cserving as the control terminals, respectively, whereas the relayterminal 12 d serves as the output terminal. In the object circuitry No.2, the relay 2B is employed under a condition where the three trimmerjoint portions 9 d, 9 e, 9 f are cut out. Then, electric power issupplied from the relay terminal 12 e, and the pair of the relayterminals 12 f, 12 g serve as the control terminals, respectively,whereas the relay terminal 12 h serves as the output terminal. In theobject circuitry No. 8, the relays 2C, 2D are employed under a conditionwhere the two trimmer joint portions 9 g, 9 h are cut out. Then,electric power is supplied from the power supply bus bar 3 via the fuse16 c, and the pair of the relay terminals 12 j, 12 k serving as thecontrol terminals, respectively, whereas the relay terminals12 l, 12 o,12 p serve as the output terminals, respectively.

[0044] From the foregoing description given above, in the firstpreferred embodiment, the presence of the unit case (not shown)containing the plurality of relays 2A to 2D which incorporate the powersupply bus bras 3, respectively, through which electric power issupplied to the respective relays 2A to 2D via the respective fuses 16 ato 16 d enables the relay unit 1 containing the plurality of fuses 16 ato 16 d in the vicinities of the plurality of relays 2A to 2D,respectively, to be constructed in a compact structure. In addition,since electric power is supplied to the respective fuses 16 a to 16 dvia the power supply bus bar 3, there is no need for providingelectrical connection using discrete electric wirings, with a resultantimprovement in workability in an assembly of the relay unit.

[0045] In the first preferred embodiment, further, the presence of theswitch connector bus bars 5 a to 5 d, in one part, integrally formedwith the downstream fuse joint portions 11 a to 11 d and the relayterminals 12 a, 12 e, 12 i, 12 m, respectively, enables the relayterminals 12 a, 12 e, 12 i, 12 m to be used for supplying electric powerto the associated relays 2A to 2D without passing power supply currentthrough the relevant fuses 16 a to 16 d. As such, in the absence of therelevant fuses 16 a to 16 d which are mounted, it is possible to use therelays 2A to 2D as independent components or through-circuits as viewedin the object circuitries Nos. 2 and 9.

[0046] In the first preferred embodiment, further, the presence of theswitch connector bus bars 5 a to 5 d, in one part, integrally formedwith the downstream fuse joint portions 11 a to 11 d and the relayterminals 12 a, 12 e, 12 i, 12 m, respectively, both of which extend inopposed relationship allows the downstream fuse joint portions 11 a to11 d and the relay terminals 12 a, 12 e, 12 j, 12 m to be located indispersed areas within the unit case. Accordingly, the fuse mountingareas and the connector mounting areas are separately located indifferent minimum areas, resulting in the relay unit 1 formed in asimplified structure with a compact configuration. In the firstpreferred embodiment, also, although the downward fuse joint portions 11a to 11 d protrude upward and the relay terminals 12 a, 12 e, 12 i, 12 mprotrude downward from respective body sections of the switch connectorbus bars 5 a to 5 d, it is suffice for the downward fuse joint portionsand the relay terminals not to be formed in the same orientation, and amodification may be made such that the downward fuse joint portions 11 ato 11 d protrude upward while the relay terminals 12 a, 12 e, 12 i, 12 mprotrude in a lateral direction, is desired.

[0047] In the aforementioned first preferred embodiment, further, thepresence of the plurality of pairs of fuse joint portions 15 a to 15 dformed with the downstream fuse joint portions 11 a to 11 d, integrallyformed with the respective switch connector bus bars 5 a to 5 d of theplurality of relays, and the upstream fuse joint portions 13 a to 13 d,integrally formed with the power supply bus bar 3, which are located inopposed relationship to one another, enables the fuse joint portions 15a to 15 d to be constructed in a simplified structure with a minimumnumber of component parts. Thus, the relay unit may be simplified instructure to have a compact configuration.

[0048] In the relay unit 1 of the first preferred embodiment, also, itis possible for various relay circuit patterns to be formed merely bytrimming selected ones of the plurality of trimmer joint portions 9 a to9 j along desired trimming patterns. This results in an easy to complywith variations in desired relay circuit patterns for the mountingcircuits with a mere trimming operation at suitable trimming pointsamong the trimmer joint portions 9 a to 9 j. When it is desired tointerconnect the switch connector bars 5 a to 5 d, 6 a to 6 d, 7 a to 7d and 8 a to 8 d to one another, the trimmer joint portions 9 a to 9 j,which are joined to the switch joint bus bars 5 a to 5 d, 6 a to 6 d, 7a to 7 d and 8 a to 8 d, remain untrimmed. As a consequence, it is easyto perform a joint absorption among the switch connector bus bars 5 d, 6a to 6 d, 7 a to 7 d and 8 a to 8 d and also a joint absorption of wireharnesses (not shown).

[0049] In the first preferred embodiment discussed above, further, thepresence of the plurality of trimmer joint portions 9 a to 9 j arepreliminarily intervened between the switch connector bus bars 5 a to 5d and the relevant coil connector bus bars 7 a to 7 d within therespective relays 2A to 2D and, within the different relays 2A to 2D,the plurality of trimmer joint portions 9 a to 9 j are intervenedbetween the pairs of the switch connector bus bars 5 a to 5 d and 6 a to6 d and the switch connector bus bars 5 a to 5 d allows the trimmerjoint portions 9 a, 9 d, 9 g, 9 j formed in the relays 2A to 2D withinthe relay unit 1 to be selectively trimmed. As such, a plurality ofpairs of coil connector terminals 12 b, 12 c, 12 f, 12 g, 12 j, 12 k, 12n, 12 o can be used as respective control terminal pairs and used asthrough-circuits without trimming the aforementioned trimmer jointportions 9 a, 9 d, 9 g, 9 j. Further, selectively trimming the trimmerjoint portions 9 b, 9 c, 9 e, 9 f, 9 h, 9 i intervening between thedifferent relays 2A to 2D allows the neighboring relays 2A to 2D to beformed into independent circuitries which are separate from one anotherand, without trimming the aforementioned trimmer joint portions 9 b, 9c, 9 e, 9 f, 9 h, 9 i, the neighboring relays 2A to 2D may be utilizedas mixed circuitries. Consequently, it is possible for a variety ofcircuitries in various circuit patterns to be obtained in an easyfashion in a low manufacturing cost.

[0050] In the aforementioned first preferred embodiment, further, sincethe switch connector circuit components and the coil connector circuitcomponents are composed of the switch connector bus bars 5 a to 5 d and6 a to 6 d and the coil connector bus bars 7 a to 7 d and 8 a to 8 d, asingle bus bar forming die may be prepared for complying with thevarious circuit patterns of the mounting circuit, with a resultantcontribution in a reduction of the manufacturing cost of the bus barforming die. Also, since the respective circuit bodies have increasedstrengths, the respective circuit bodies may be integrally formed withthe respective terminals.

[0051] In the first preferred embodiment, further, since the respectiveswitch connector bus bars 5 a to 5 d and 6 a to 6 d and the coilconnector bus bars 7 a to 7 d and 8 a to 8 d are formed with therespective relay terminals 12 a to 12 p to be connected to therespective connectors, there is no need for additionally preparing therelay terminals separate from the relays 2A to 2D, the relay unit may besimplified in structure to have a compact configuration.

[0052] In the first preferred embodiment, also, although the relay unit1 has been shown and described as being composed of the four sets of therelays 2A to 2D, the relay unit 1 may include two, three, or more thanfive relays. In the aforementioned preferred embodiment, further, sincethe relay unit 1 includes the four sets of the relays 2A to 2D and thenine patterns, the relay unit 1 may have the mounting circuitries in thenumber of circuit patterns corresponding to the fourth power of nine.

[0053] FIGS. 10 to 12 show a relay unit and an electrical junction boxof a second preferred embodiment according to the present invention.FIG. 10 is a cross sectional view (involving a front view of the relayaccording to the present invention) of the electrical junction boxaccording to the present invention. FIG. 11 is a plan view of theelectrical junction box shown in FIG. 10, and FIG. 12 is an enlargedview illustrating the relays and the fuses shown in FIG. 10. In thedescription, the words “upward” or “downward” are used on the basis of areference in conjunction with the structure shown in FIG. 10.

[0054] In FIGS. 10 to 12, the electrical junction box to be mounted to avehicle such as an automobile includes a box body 21 (which correspondsto the unit case described with reference to the first preferredembodiment) which is comprised of a main cover 22 made of plastic resin,an undercover 23 made of plastic resin, the plurality of fuses 24arrayed in a row in parallel relationship with respect to one anotherand accommodated in the main cover 22, the plurality of fuses 25 arrayedin a row in parallel relationship with respect to one another andaccommodated in the undercover 23, and the pair of power supply bus bars26.

[0055] Further, the box body 21 is formed with an electric power supplysection 27 to which electric power is supplied from an electric powersupply such as a battery (not shown), and a plurality of connector jointportions 28 which are connected to the associated relays and theassociated fuses 24.

[0056] The main cover 22 is formed with an upper wall 30 and a rear wall31 which form a hood portion 29 of the electric power supply section 27,a plurality of fuse cavities 32 associated with the respective fuses 24,and a plurality of lock portions 33 which engages the undercover 23.

[0057] The upper wall 30 formed on the main cover 22 has a flat shapehaving a distal end whose inner surface is formed with a lock segment 35to clamp a connector 34 for supplying electric power to the power supplysection 27. Also, the upper wall 30 and the rear wall 31 are formed in ashape so as to intersect with one another at an inner base portion ofthe upper wall 30.

[0058] The respective fuse cavities 32 have desired profiles to allowthe associated fuses 24 to be inserted from the respective distalportions in a downward direction. Further, each of the fuse cavities 32is formed with a terminal receiver compartment 36. In addition, eachcavity 32 is formed so as to penetrate in upper and lower directions. Inthe illustrated embodiment, each fuse cavity has the same shape as thatof the related art structure.

[0059] In FIG. 10, further, the fuse cavities 32, located at first,third and fifth locations counting from the right side, refer to otherfuse cavities which are defined in appended claims. These fuse cavitiesare located to effectively use spaces in a row in which the relays 25are arrayed and between the neighboring fuses 24 to which the associatedrelays 25 are connected.

[0060] The lock portions 33 are integrally formed with a fuse cavityforming wall 37, on which the fuse cavities 32 are formed, and extenddownward from a peripheral edge thereof.

[0061] The undercover 23 is formed with a hood body 38 and a rear wall39 which form the hood portion 29, a plurality of relay compartments 40for accommodating the relays 25, respectively, a plurality ofthrough-holes 41 formed between the adjacent relay compartments 40, aplurality of hood compartments 42 which form the connector jointportions 28, respectively, and a plurality of lock segments 43 formed inrespective projections which engage the lock portions 33 of the maincover 22.

[0062] The hood body 38 is formed in the undercover 23 in a C-shape incross section (as viewed from a connecting direction of the connector34). Also, the hood body 38 is formed in a structure to clamp the upperwall 30 of the main cover 22 through some suitable means.

[0063] On the other hand, the rear wall 39, which is formed at a bottomarea of the hood 38, is formed to allow the aforementioned power supplybus bar 26 to be sandwiched between the rear wall 31 of the main cover22 and the rear wall 39 to retain the same in a fixed place. Further,the rear wall 39 forms a part of the relay compartment 40, which isclosest to the electric power supply section 27, and also serves as aresting member to support a substrate 54 which will be discussed later.

[0064] The relay compartment 40 is shaped to have a profile to complywith an external shape of the relay 25 for fully accommodating the relay25. Also, the relay compartment 40 has a bottom wall formed with aplurality of terminal insertion slots 44 which communicate with an innerside of the relay compartment 40. Also, the through-hole 41 communicateswith an inner side of the hood portion 42 in the same manner as theterminal insertion slots 44.

[0065] Although each fuse 24 is of the same structure as the related artpractice and a detailed description of the same is herein omitted, eachfuse 24 is constructed of a tab-shaped upstream terminal 45, atab-shaped downstream terminal 46, and a soluble body (not shown)intervening between the upstream and downstream terminals.

[0066] The plurality of relays 25 are arrayed in five sets. Thus, likein the first preferred embodiment, the relay unit is comprised of fivesets of relay switch elements (not shown), relay coil elements (notshown) and basic bus bar circuit components (not shown). Since the basicbus bar circuit components have the same structures as those of thefirst preferred embodiment except for the number of sets of the circuitcomponents, a detailed description of the same is herein omitted.Further, the relay 25 is constructed of a circuit substrate (not shown)which is made of plastic resin, an outer cover 47 formed in a box shapeand enclosing the circuit substrate, a relay coil (not shown) internallylocated in the outer cover 47, a one terminal 48 which extends upwardfrom an upper wall of the outer cover 47, and three other terminals(with only two terminals being shown) 49 which extend from theaforementioned circuit substrate via the terminal insertion slots 44. Inthe illustrated preferred embodiment, further, the one terminal 48extends straightly upward, whereas the other terminals (which correspondto the relay terminals 12 a to 12 p of the first preferred embodiment)49 extend straightly downward.

[0067] The one terminal 48 is formed at its one end with a fuseconnector portion 50 shaped in a bifurcated profile to be connected tothe downstream terminal 46 of the fuse 24. Further, the other end of theone terminal 48 is formed with a contact which is located inside theouter cover 47.

[0068] On the other hand, all of the three terminals 49 are formed intab-shapes and form the connector joint portions 28, respectively.

[0069] It is to be noted that the one terminal 48 may not extend throughthe upper wall of the outer cover 47 but through a side wall thereof. Insuch a case, although the relays 24 are arrayed in a right and leftdirection of the relays 25 such that the relay unit may encounter adifficulty in obtaining the same miniaturization result as that obtainedin the box body 21 of the presently filed preferred embodiment, it ispossible to obtain an improved workability in a reliable manner as willbe described later.

[0070] The aforementioned power supply bus bar 26 is comprised of a tab51 which forms a part of the power supply section 27, a firstintermediate component 52 which is sandwiched between the rear wall 31of the main cover 22 and the rear wall 39 of the undercover 23, and asecond intermediate component 53 located in a plane parallel to theaforementioned upper walls of the relays 25. Further, secondintermediate component 53 of the power supply bus bar 26 is placed onthe circuit substrate made of plastic resin and fixed thereto.

[0071] The tab 51 of the power supply bus bar 26 is located so as toprotrude inside the hood body 38 to allow electric power to be suppliedthrough the tab 51. Further, the second intermediate component 53 of thepower supply bus bar 26 is formed with a plurality of upwardly extendingfuse connector portions 55 to which the upstream terminals 45 of thefuses 24 are connected, respectively. Each connector portion 55 isformed in the same shape as the fuse connector portion 50 formed in theone terminal 48 (with the fuse connector portions 55 being located in arear side of the fuse connector portion 50 in FIGS. 12 and 14 andbearing the respective reference numerals enclosed in parentheses).

[0072] Located on respective distal ends of the rear wall 39 and therelay compartments 40 is the circuit substrate 54, to which theaforementioned power supply bus bar 26 and the plurality of bus bars 56,which is different from the power supply bus bar 26, are fixedlyconnected. Further, the circuit substrate 54 is formed with a pluralityof through-bores 57 through which the associated terminals 48 of therespective relays 25 extend, and a plurality of through-holes 58 locatedfor the bus bars 56. The through-holes 58 are formed in alignment withthe through-holes 41 of the undercover 23.

[0073] One end of each bus bar 56, which is placed on the circuitsubstrate 54 and fixed thereto independently of the power supply bus bar26, is formed with a plurality of fuse connector portions 59 to beconnected to the downstream terminals 46 of the associated fuses 24 tobe inserted through the first, third and fifth fuse cavities 32countingfrom the right side in FIG. 12. Also, the other end of each bus bar 56is formed with an elongated tab 60 which extends through thethrough-hole 58 of the circuit substrate 54 and the through-hole 41 ofthe undercover 23 and which forms a part of each connector portion 28together with the other terminals 49 of the relay 25.

[0074] Now, a detailed description will be given below on how the boxbody 21 of the electrical junction box of the present invention isassembled.

[0075] Initially, a first step is carried out for placing and receivingthe relays 25 in the respective relay compartments 40 of the undercover23. In particular, each relay 25 is inserted into the relevant relaycompartment 40 from the side of the other terminals 49. Then, upon fullyreceipt of the relay 25, the other terminals 49 of the relay 25 protrudeinto the relevant hood portion 42 via the associated terminal insertionslots 44. Also, only the one terminal 48 of the relay 25 extends upwardfrom the relay compartment 40.

[0076] Under such a condition, a second step is carried out for locatingthe circuit substrate 54, on which the power supply bus bars 26 and 56are placed and fixed thereto, on the upper distal ends of the respectiverelay compartments 40. In particular, the circuit substrate 54 is placedon the upper distal ends of the relay compartment 40 while allowing theone terminal 48 of the relay 25 to be inserted through the relevantthrough-hole 57 while, at the same time, allowing the tab 60 of the busbar 56 to be inserted through the relevant through-hole 41 of theundercover 23. Then, the circuit substrate 54 is fully placed over theupper distal ends of the respective relay compartments 40 and, when thetab 60 of the bas bar 56 protrudes inside the hood portion 42, theconnector joint portion 28 is formed.

[0077] In a consecutive operation, a third step is carried out forpermitting the main cover 22 to be mated with the undercover 23. Whenthe lock portions 33 of the main cover 22 engage the lock segments 43 ofthe undercover 23, the power supply bus bar 26 and the associatedcircuit substrate 54 are held in a sandwiched state between the maincover 22 and the undercover 23 and retained in a fixed place. Also, inthis instance, terminal receiver compartment 36 of each fuse cavity 32receives therein the fuse connector portion 50 of the one terminal 48 ofthe relay 25, the fuse connector portion 55 of the power supply bus bar26, the fuse connector portion 59 of the bus bar 56 and the fuseconnector portion 55 of the power supply bus bar 26.

[0078] Then, lastly, under a circumstance described above, the fuses 24are inserted into the relevant fuse cavities 32 such that the upstreamterminal 45 and the downstream terminal 46 are connected to the relevantfuse connector portion 50 of the one terminal 48 of the relay 25, thefuse connector portion 55 of the power supply bus bar 26, the fuseconnector portion 59 of the bus bar 56 and the fuse connector portion 55of the power supply bus bar 26, thereby completing a series ofassembling steps.

[0079] As will be appreciated from the foregoing description, in thesecond preferred embodiment, the presence of the box body (whichcorresponds to the unit case described with reference to the firstpreferred embodiment) containing the plurality of relays 25 and thepower supply bus bar 26 for supplying power supply current to theserelays 25 allows the relay unit, in which the plurality of fuses arecontained in the vicinity of the plurality of relays in a single boxbody, to be provided. This results in the relay unit, which incorporatesthe fuses 24, and accordingly the electrical junction box to bemanufactured in compact structures. Also, since power supply current isapplied to the respective fuses 24 via the power supply bus bar 26,there is no need for discrete electric wirings to be connected, therebyhighly improving workability in assembly.

[0080] According to the relay 25 of the second preferred embodiment,further, since the one terminal 48 and the other terminals 49 are formedat locations different from one another while the one terminal 48 isformed with the fuse connector portion 50, it is possible for thedownstream terminal 46 of each fuse 24 to be directly connected to theconnector portion 50. Accordingly, there is no need for providingdiscrete electrical wirings that would be required between the relays 25and the fuses 24 in the related art structure, providing an ease oflaminating the fuses 24 in the upper side of the relays 25 for therebyimproving an assembling workability.

[0081] According to the electrical junction box of the presentinvention, also, the presence of the relay 25 having the aforementionedadvantages enables the electrical junction box to be formed such thatthe downstream terminals 46 of the fuses 24 can be directly coupled tothe fuse connector portions 50 of the relays 25. That is, inserting thefuses 24 into the fuse cavities 32, under a condition wherein the relays25 are received in the relay compartments 40, allows the electricaljunction box to be constructed such that the one terminal 48, which isinserted into the relevant fuse cavity 32, of each relay 25 is broughtinto direct electrical contact with the downstream terminal 46 of therelevant fuse 24. Consequently, the relays 25 and the fuses 24 can beconnected to one another without the need for the discrete electricalwirings, resulting in an improved workability.

[0082] According to the electrical junction box of the presentinvention, the presence of the relay 25 having the advantages describedabove enables the fuses 24 to be received in the stacked state with therelevant relays 25 within the electrical junction box. Thus, such anarrangement allows the electrical junction box to be miniaturized.

[0083] According to the electrical junction box, further, the presenceof the connector joint portions 28 allows the electrical junction box tobe constructed such that a package of the wire harnesses can beconnected to the other terminals 49 of each relay 25 through a connectorjoint. Therefore, there is no need for troublesome load works forindividually locating separate terminals with electrical wirings ontorelevant positions corresponding to the other terminals 49 of the relay25 one by one, with a resultant improved assembling workability.

[0084] According to the electrical junction box of the presentinvention, furthermore, the presence of the power supply bus bar 26enables electrical connection between the upstream terminal 45 of thefuse 24 and the power supply section 27. As a consequent, there is noneed for connecting the above component parts together with electricwires one by one, resulting in an improved workability.

[0085]FIG. 13 is a cross sectional view illustrating an electricaljunction box of a third preferred embodiment according to the presentinvention, with like parts bearing the same reference numerals as thoseused in the aforementioned illustrated embodiments for omitting aredundant description of the same component parts. In the fourthpreferred embodiment, the electrical junction box is constructed of abox body 61 and a lower cover 62, with the box body 61 being formed withconnector joint portions 63 whose bottom walls are spaced from a bottomwall 64 of the lower cover 62 by a given distance. Also, it is to benoted that the box body 61 and the lower cover 62 are fixedly secured toone another with suitable fixtures.

[0086] More particularly, the box body 61 is constructed of a main cover65, the aforementioned fuses 24, the aforementioned relays 25 and theaforementioned power supply bus bar 26. Further, the main cover 65 isformed with a hood section 66, relay compartments 67 and fuse cavities68 in a sequence from the bottom wall 64 of the lower cover 62. Each ofthe relay compartments 67 is formed with a slit 69 with which a lock 70of the relay 25 is brought into engagement when the relay 25 is receivedin the relay compartment 67 to preclude the relay 25 from beingdislocated.

[0087] Also, the aforementioned fuses 24, the aforementioned relays 25and the aforementioned power supply bus bar 26 are electricallyconnected to one another in the same manner as those of the preferredembodiments described above. Therefore, a detailed description of thesame is herein omitted.

[0088] With the structure described above, when the relay 25 is receivedin the relay compartment 67, the other terminals 49 protrude into thehood section 66 to form the connector joint portion 63. Then, theconnector 71 is connected to the connector joint portion 63 through theconnector coupling.

[0089] Since the connector joint portion 63 is spaced from the bottomwall 64 of the lower cover 62 by the given distance, a sufficient spaceis enhanced for achieving the connector coupling of the connector 71 ofa wire harness 72 while providing an improved receiving capacity for thewire harness 72, etc. Thus, it is possible for the workability to behighly improved, with the other aforementioned advantages being alsoobtained in the presently filed preferred embodiment.

[0090] Also, with a specific arrangement wherein the connector 71 isfixed to the bottom wall 64 of the lower cover 62, the connector jointportion 63 may be readily coupled to the connector 71 during anassembly, with a resultant improved workability.

[0091] From the foregoing description given above, it is to be notedthat various other modifications may be made without departing thespirit of the present invention. For example, without forming the fuseconnector portion 50 at the one terminal 48 which in turn remains in thetab shape, it is possible for the downstream terminal 46 of the fuse 24to be electrically connected by means of a male-female type junctionterminal of a structure in the related art. In such a case, the relay ofthe present invention may be featured as follows:

[0092] (1) The relay is featured in that the one terminal, whichcorresponds to the downstream terminal of the fuse, is arranged to belocated in a different position so as to extend in an orientationdifferent from that in which the other terminals extend.

[0093] (2) In the relay (1) defined above, the one terminal is formedwith a fuse connector portion which enables the aforementioneddownstream terminal of the aforementioned fuse to be directly connectedto the aforementioned one terminal.

[0094] It will now be appreciated from the foregoing description that inaccordance with the present invention, the presence of the plurality ofrelays and the power supply bus bar contained in a particular area inclose proximity to one another to apply electric power supply to therespective relays via the relevant fuses allows the relay unit, which isenabled to also contain the associated fuses in the vicinity of therelevant relays, to be provided. This results in the relay unit which issimple and compact in structure even contained with the relevant fuses.Further, the presence of the power supply bus bar contained in the relayunit for supplying power supply current to various component parts viathe respective fuses eliminates the need for discrete electric wiringswhile highly increasing workability in an assembly of the relay unit.

[0095] Another important advantage of the present invention concerns theelectrical junction box containing the plurality of relays and the powersupply bus bar through which power supply current is supplied to therespective relays via the relevant fuses for thereby providing a compactand simplified structure at a low manufacturing cost while eliminatingthe need for preparing discrete electric wirings specifically designedfor the particular electrical junction box.

[0096] While specific embodiments of the present invention have beendescribed in detail, it will be appreciated to those skilled in the artthat various modifications and alternatives to those details could bedeveloped in light of the overall teachings of the disclosure.Accordingly, the particular arrangements disclosed are meant to beillustrative only and not limiting the scope of the invention which isto be given the full breadth of the following claims and all equivalentsthereof.

What is claimed is:
 1. A relay unit comprising: a plurality of relays;and a power supply bus bar supplying power supply current to saidplurality of relays; wherein said power supply bus bar allows powersupply current to be supplied to said plurality of relays via respectivefuses.
 2. The relay unit according to claim 1, wherein: each of saidrelays includes a pair of switch connector circuit components betweenwhich a relay switch element is intervened and a pair of coil connectorcircuit components between which a relay coil element is intervened,wherein one of said switch connector circuit components is formed with adownstream fuse connector portion to which each of said fuses iselectrically coupled and a relay terminal to which a connected iselectrically coupled.
 3. The relay unit according to claim 2, wherein:the other one of said switch connector circuit components and said pairof coil circuit are formed with relay terminals to be electricallyconnected to relevant connectors, respectively.
 4. The relay unitaccording to claim 1, wherein: said power supply bus bar is located atan inner surface of a unit case.
 5. The relay unit according to claim 2,wherein: said power supply bus bar is formed with an upstream fuseconnector portion; and said downstream fuse connector portion formed onsaid one of said switch connector circuit components and said upstreamfuse connector portion formed on said power supply bus bar are locatedin an opposed relationship to form a pair of fuse connector components.6. An electrical junction box comprising: a plurality of relays; and apower supply bus bar supplying power supply current to said plurality ofrelays; wherein said power supply bus bar allows power supply current tobe supplied to said plurality of relays via respective fuses.
 7. Theelectrical junction box according to claim 6, wherein: each of saidplurality of relays has one terminal formed with a fuse connectorportion; and further comprising: a plurality of fuses each formed with adownstream terminal to which said one terminal is electrically coupledvia said fuse connector portion; and a box body enclosing at least saidplurality of relays and said plurality of fuses; wherein said box bodyhas a plurality of relay compartments receiving said plurality ofrelays, respectively, and a plurality of fuse cavities receiving saidplurality of fuses, respectively.
 8. The electrical junction boxaccording to claim 7, wherein: said box body is formed to have astructure wherein said one terminal of said each relay is located at aposition opposite to the other terminal of said each relay to allow eachof said plurality of fuses to be located in a stacked state with saidone terminal of said each relay.
 9. The electrical junction boxaccording to claim 8, wherein: said box body further has a plurality ofconnector joint portions each in the vicinity of said other terminal ofsaid each relay to allow each connector fixed to a wire harness to becoupled to said other terminal.
 10. The electrical junction boxaccording to claim 9, further comprising: a lower cover to which saidbox body is mounted such that said each connector joint portion isseparated from a bottom wall of said lower cover by a given distance.11. The electrical junction box according to claim 8, wherein: said boxbody has another plurality of fuse cavities formed along said pluralityof relays, each formed between neighboring fuses connected to saidrespective relays for receiving another plurality of fuses which are outof electrical connection with said plurality of fuses.
 12. Theelectrical junction box according to claim 7, further comprising: atleast upstream terminals formed on said plurality of fuses,respectively; and a power supply bus bar providing electrical connectionbetween said upstream terminals and an electrical power supply sectionexternally applied with electric power supply.